Really the only reason to build out your own frame is to get components that aren't available in the factory build. In that regard one isn't comparing the price of the complete bike to the frame built out, but rather the cost of the complete bike + the change orders compared to the frame built out. On that basis it may not be cheaper to get the complete bike.

Another option if you aren't planing on making a lot of changes is to work with your bike shop to see the cost of making various changes to the complete bike, like swaping out saddles, etc... The last complete bike I bought, not the LHT (wasn't locally sold) I got credits for supplying my own brake and subsituting bar ends for brifters, I got a "free" brooks.

While it is fun to mess around with the bike options, I would recomend taking the complete bike and riding it for a while before deciding on major changes. You may decide to go way up market, and want to sell the LHT, or you may be satisfied with the bike as is. It is possible to do a lot of research and invent a lot of needs based on online chat when the picture will become chrystal clear after the first few thousand miles.

As far as learning bike assembly/repair is concerned, touring is mostly basic maintenance like adjusting brakes and deraileurs (youtube):

http://www.youtube.com/results?searc...rch_type=&aq=f

With assembling a bike, you don't learn stuff like replacing drive side spokes, and will have to contend with prep you are never liely to repeat on the road.